Metamath Proof Explorer


Theorem dvgrat

Description: Ratio test for divergence of a complex infinite series. See e.g. remark "if ( abs( ( a( n + 1 ) ) / ( an ) ) ) >_ 1 for all large n..." in https://en.wikipedia.org/wiki/Ratio_test#The_test . (Contributed by Steve Rodriguez, 28-Feb-2020)

Ref Expression
Hypotheses dvgrat.z ⊢ Z = ℤ ≥ M
dvgrat.w ⊢ W = ℤ ≥ N
dvgrat.n ⊢ φ → N ∈ Z
dvgrat.f ⊢ φ → F ∈ V
dvgrat.c ⊢ φ ∧ k ∈ Z → F ⁡ k ∈ ℂ
dvgrat.n0 ⊢ φ ∧ k ∈ W → F ⁡ k ≠ 0
dvgrat.le ⊢ φ ∧ k ∈ W → F ⁡ k ≤ F ⁡ k + 1
Assertion dvgrat ⊢ φ → seq M + F ∉ dom ⁡ ⇝

Proof

Step Hyp Ref Expression
1 dvgrat.z ⊢ Z = ℤ ≥ M
2 dvgrat.w ⊢ W = ℤ ≥ N
3 dvgrat.n ⊢ φ → N ∈ Z
4 dvgrat.f ⊢ φ → F ∈ V
5 dvgrat.c ⊢ φ ∧ k ∈ Z → F ⁡ k ∈ ℂ
6 dvgrat.n0 ⊢ φ ∧ k ∈ W → F ⁡ k ≠ 0
7 dvgrat.le ⊢ φ ∧ k ∈ W → F ⁡ k ≤ F ⁡ k + 1
8 3 1 eleqtrdi ⊢ φ → N ∈ ℤ ≥ M
9 eluzelz ⊢ N ∈ ℤ ≥ M → N ∈ ℤ
10 8 9 syl ⊢ φ → N ∈ ℤ
11 uzid ⊢ N ∈ ℤ → N ∈ ℤ ≥ N
12 11 2 eleqtrrdi ⊢ N ∈ ℤ → N ∈ W
13 10 12 syl ⊢ φ → N ∈ W
14 simpr ⊢ φ ∧ k = N → k = N
15 14 eleq1d ⊢ φ ∧ k = N → k ∈ W ↔ N ∈ W
16 14 fveq2d ⊢ φ ∧ k = N → F ⁡ k = F ⁡ N
17 16 fveq2d ⊢ φ ∧ k = N → F ⁡ k = F ⁡ N
18 17 breq2d ⊢ φ ∧ k = N → 0 < F ⁡ k ↔ 0 < F ⁡ N
19 15 18 imbi12d ⊢ φ ∧ k = N → k ∈ W → 0 < F ⁡ k ↔ N ∈ W → 0 < F ⁡ N
20 2 eleq2i ⊢ k ∈ W ↔ k ∈ ℤ ≥ N
21 1 uztrn2 ⊢ N ∈ Z ∧ k ∈ ℤ ≥ N → k ∈ Z
22 20 21 sylan2b ⊢ N ∈ Z ∧ k ∈ W → k ∈ Z
23 3 22 sylan ⊢ φ ∧ k ∈ W → k ∈ Z
24 23 5 syldan ⊢ φ ∧ k ∈ W → F ⁡ k ∈ ℂ
25 absgt0 ⊢ F ⁡ k ∈ ℂ → F ⁡ k ≠ 0 ↔ 0 < F ⁡ k
26 24 25 syl ⊢ φ ∧ k ∈ W → F ⁡ k ≠ 0 ↔ 0 < F ⁡ k
27 6 26 mpbid ⊢ φ ∧ k ∈ W → 0 < F ⁡ k
28 27 ex ⊢ φ → k ∈ W → 0 < F ⁡ k
29 3 19 28 vtocld ⊢ φ → N ∈ W → 0 < F ⁡ N
30 13 29 mpd ⊢ φ → 0 < F ⁡ N
31 0red ⊢ φ → 0 ∈ ℝ
32 14 eleq1d ⊢ φ ∧ k = N → k ∈ Z ↔ N ∈ Z
33 16 eleq1d ⊢ φ ∧ k = N → F ⁡ k ∈ ℂ ↔ F ⁡ N ∈ ℂ
34 32 33 imbi12d ⊢ φ ∧ k = N → k ∈ Z → F ⁡ k ∈ ℂ ↔ N ∈ Z → F ⁡ N ∈ ℂ
35 5 ex ⊢ φ → k ∈ Z → F ⁡ k ∈ ℂ
36 3 34 35 vtocld ⊢ φ → N ∈ Z → F ⁡ N ∈ ℂ
37 3 36 mpd ⊢ φ → F ⁡ N ∈ ℂ
38 37 abscld ⊢ φ → F ⁡ N ∈ ℝ
39 31 38 ltnled ⊢ φ → 0 < F ⁡ N ↔ ¬ F ⁡ N ≤ 0
40 30 39 mpbid ⊢ φ → ¬ F ⁡ N ≤ 0
41 10 adantr ⊢ φ ∧ F ⇝ 0 → N ∈ ℤ
42 38 adantr ⊢ φ ∧ F ⇝ 0 → F ⁡ N ∈ ℝ
43 simpr ⊢ φ ∧ F ⇝ 0 → F ⇝ 0
44 2 fvexi ⊢ W ∈ V
45 44 mptex ⊢ i ∈ W ⟼ F ⁡ i ∈ V
46 45 a1i ⊢ φ ∧ F ⇝ 0 → i ∈ W ⟼ F ⁡ i ∈ V
47 24 adantlr ⊢ φ ∧ F ⇝ 0 ∧ k ∈ W → F ⁡ k ∈ ℂ
48 eqidd ⊢ φ ∧ F ⇝ 0 ∧ k ∈ W → i ∈ W ⟼ F ⁡ i = i ∈ W ⟼ F ⁡ i
49 simpr ⊢ φ ∧ F ⇝ 0 ∧ k ∈ W ∧ i = k → i = k
50 49 fveq2d ⊢ φ ∧ F ⇝ 0 ∧ k ∈ W ∧ i = k → F ⁡ i = F ⁡ k
51 50 fveq2d ⊢ φ ∧ F ⇝ 0 ∧ k ∈ W ∧ i = k → F ⁡ i = F ⁡ k
52 simpr ⊢ φ ∧ F ⇝ 0 ∧ k ∈ W → k ∈ W
53 fvex ⊢ F ⁡ k ∈ V
54 53 a1i ⊢ φ ∧ F ⇝ 0 ∧ k ∈ W → F ⁡ k ∈ V
55 48 51 52 54 fvmptd ⊢ φ ∧ F ⇝ 0 ∧ k ∈ W → i ∈ W ⟼ F ⁡ i ⁡ k = F ⁡ k
56 2 43 46 41 47 55 climabs ⊢ φ ∧ F ⇝ 0 → i ∈ W ⟼ F ⁡ i ⇝ 0
57 abs0 ⊢ 0 = 0
58 56 57 breqtrdi ⊢ φ ∧ F ⇝ 0 → i ∈ W ⟼ F ⁡ i ⇝ 0
59 47 abscld ⊢ φ ∧ F ⇝ 0 ∧ k ∈ W → F ⁡ k ∈ ℝ
60 55 59 eqeltrd ⊢ φ ∧ F ⇝ 0 ∧ k ∈ W → i ∈ W ⟼ F ⁡ i ⁡ k ∈ ℝ
61 2fveq3 ⊢ i = N → F ⁡ i = F ⁡ N
62 61 breq2d ⊢ i = N → F ⁡ N ≤ F ⁡ i ↔ F ⁡ N ≤ F ⁡ N
63 62 imbi2d ⊢ i = N → φ → F ⁡ N ≤ F ⁡ i ↔ φ → F ⁡ N ≤ F ⁡ N
64 2fveq3 ⊢ i = k → F ⁡ i = F ⁡ k
65 64 breq2d ⊢ i = k → F ⁡ N ≤ F ⁡ i ↔ F ⁡ N ≤ F ⁡ k
66 65 imbi2d ⊢ i = k → φ → F ⁡ N ≤ F ⁡ i ↔ φ → F ⁡ N ≤ F ⁡ k
67 2fveq3 ⊢ i = k + 1 → F ⁡ i = F ⁡ k + 1
68 67 breq2d ⊢ i = k + 1 → F ⁡ N ≤ F ⁡ i ↔ F ⁡ N ≤ F ⁡ k + 1
69 68 imbi2d ⊢ i = k + 1 → φ → F ⁡ N ≤ F ⁡ i ↔ φ → F ⁡ N ≤ F ⁡ k + 1
70 38 adantr ⊢ φ ∧ N ∈ ℤ → F ⁡ N ∈ ℝ
71 70 leidd ⊢ φ ∧ N ∈ ℤ → F ⁡ N ≤ F ⁡ N
72 71 expcom ⊢ N ∈ ℤ → φ → F ⁡ N ≤ F ⁡ N
73 38 ad2antrr ⊢ φ ∧ k ∈ W ∧ F ⁡ N ≤ F ⁡ k → F ⁡ N ∈ ℝ
74 24 adantr ⊢ φ ∧ k ∈ W ∧ F ⁡ N ≤ F ⁡ k → F ⁡ k ∈ ℂ
75 74 abscld ⊢ φ ∧ k ∈ W ∧ F ⁡ N ≤ F ⁡ k → F ⁡ k ∈ ℝ
76 2 peano2uzs ⊢ k ∈ W → k + 1 ∈ W
77 ovex ⊢ k + 1 ∈ V
78 eleq1 ⊢ i = k + 1 → i ∈ W ↔ k + 1 ∈ W
79 78 anbi2d ⊢ i = k + 1 → φ ∧ i ∈ W ↔ φ ∧ k + 1 ∈ W
80 fveq2 ⊢ i = k + 1 → F ⁡ i = F ⁡ k + 1
81 80 eleq1d ⊢ i = k + 1 → F ⁡ i ∈ ℂ ↔ F ⁡ k + 1 ∈ ℂ
82 79 81 imbi12d ⊢ i = k + 1 → φ ∧ i ∈ W → F ⁡ i ∈ ℂ ↔ φ ∧ k + 1 ∈ W → F ⁡ k + 1 ∈ ℂ
83 eleq1 ⊢ k = i → k ∈ W ↔ i ∈ W
84 83 anbi2d ⊢ k = i → φ ∧ k ∈ W ↔ φ ∧ i ∈ W
85 fveq2 ⊢ k = i → F ⁡ k = F ⁡ i
86 85 eleq1d ⊢ k = i → F ⁡ k ∈ ℂ ↔ F ⁡ i ∈ ℂ
87 84 86 imbi12d ⊢ k = i → φ ∧ k ∈ W → F ⁡ k ∈ ℂ ↔ φ ∧ i ∈ W → F ⁡ i ∈ ℂ
88 87 24 chvarvv ⊢ φ ∧ i ∈ W → F ⁡ i ∈ ℂ
89 77 82 88 vtocl ⊢ φ ∧ k + 1 ∈ W → F ⁡ k + 1 ∈ ℂ
90 76 89 sylan2 ⊢ φ ∧ k ∈ W → F ⁡ k + 1 ∈ ℂ
91 90 adantr ⊢ φ ∧ k ∈ W ∧ F ⁡ N ≤ F ⁡ k → F ⁡ k + 1 ∈ ℂ
92 91 abscld ⊢ φ ∧ k ∈ W ∧ F ⁡ N ≤ F ⁡ k → F ⁡ k + 1 ∈ ℝ
93 simpr ⊢ φ ∧ k ∈ W ∧ F ⁡ N ≤ F ⁡ k → F ⁡ N ≤ F ⁡ k
94 7 adantr ⊢ φ ∧ k ∈ W ∧ F ⁡ N ≤ F ⁡ k → F ⁡ k ≤ F ⁡ k + 1
95 73 75 92 93 94 letrd ⊢ φ ∧ k ∈ W ∧ F ⁡ N ≤ F ⁡ k → F ⁡ N ≤ F ⁡ k + 1
96 95 ex ⊢ φ ∧ k ∈ W → F ⁡ N ≤ F ⁡ k → F ⁡ N ≤ F ⁡ k + 1
97 20 96 sylan2br ⊢ φ ∧ k ∈ ℤ ≥ N → F ⁡ N ≤ F ⁡ k → F ⁡ N ≤ F ⁡ k + 1
98 97 expcom ⊢ k ∈ ℤ ≥ N → φ → F ⁡ N ≤ F ⁡ k → F ⁡ N ≤ F ⁡ k + 1
99 98 a2d ⊢ k ∈ ℤ ≥ N → φ → F ⁡ N ≤ F ⁡ k → φ → F ⁡ N ≤ F ⁡ k + 1
100 63 66 69 66 72 99 uzind4 ⊢ k ∈ ℤ ≥ N → φ → F ⁡ N ≤ F ⁡ k
101 100 impcom ⊢ φ ∧ k ∈ ℤ ≥ N → F ⁡ N ≤ F ⁡ k
102 20 101 sylan2b ⊢ φ ∧ k ∈ W → F ⁡ N ≤ F ⁡ k
103 102 adantlr ⊢ φ ∧ F ⇝ 0 ∧ k ∈ W → F ⁡ N ≤ F ⁡ k
104 103 55 breqtrrd ⊢ φ ∧ F ⇝ 0 ∧ k ∈ W → F ⁡ N ≤ i ∈ W ⟼ F ⁡ i ⁡ k
105 2 41 42 58 60 104 climlec2 ⊢ φ ∧ F ⇝ 0 → F ⁡ N ≤ 0
106 40 105 mtand ⊢ φ → ¬ F ⇝ 0
107 eluzel2 ⊢ N ∈ ℤ ≥ M → M ∈ ℤ
108 8 107 syl ⊢ φ → M ∈ ℤ
109 108 adantr ⊢ φ ∧ seq M + F ∈ dom ⁡ ⇝ → M ∈ ℤ
110 4 adantr ⊢ φ ∧ seq M + F ∈ dom ⁡ ⇝ → F ∈ V
111 simpr ⊢ φ ∧ seq M + F ∈ dom ⁡ ⇝ → seq M + F ∈ dom ⁡ ⇝
112 5 adantlr ⊢ φ ∧ seq M + F ∈ dom ⁡ ⇝ ∧ k ∈ Z → F ⁡ k ∈ ℂ
113 1 109 110 111 112 serf0 ⊢ φ ∧ seq M + F ∈ dom ⁡ ⇝ → F ⇝ 0
114 106 113 mtand ⊢ φ → ¬ seq M + F ∈ dom ⁡ ⇝
115 df-nel ⊢ seq M + F ∉ dom ⁡ ⇝ ↔ ¬ seq M + F ∈ dom ⁡ ⇝
116 114 115 sylibr ⊢ φ → seq M + F ∉ dom ⁡ ⇝